Hi kirnish,
in Do
kuwiki you simply place the image url between curly brackets:
{{
http://server.com/image.jpg}}
It's explained in
http://wiki.splitbrain.org/wiki:syntax#images_and_other_files
Directly linking from a distant server is considered bandwidth theft, you should always place a local copy
on your server and link that one. Most servers (don't know about flickr) protect themselves from BW theft.